JP6071972B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner including a permanent magnet motor.

  Ferrite magnets used in permanent magnet motors have a lower coercive force at lower temperatures, so that the resistance to the reverse magnetic field generated by the stator current decreases as the temperature decreases, and the magnet becomes easier to demagnetize. Therefore, an overcurrent protection value is set for a permanent magnet motor using a ferrite magnet so that the starting current at a low temperature and the step-out current after starting are less than the demagnetization limit current value. For permanent magnet motors with an overcurrent protection value set, if the stator current exceeds the overcurrent protection value, the energization to the stator is cut off and the motor is stopped, or immediately before the stator current exceeds the overcurrent protection value. Stall control is applied to the stator so that the stator current does not exceed the overcurrent protection value.

  The overcurrent protection value is normally set to a low value so that demagnetization does not occur even when the air conditioner is started at a low temperature, but the stator current is actually maximized when the temperature is high. Is the maximum output operation. However, since the overcurrent protection value is set to a value that takes into account demagnetization at low temperatures, it can be operated only up to the overcurrent protection value at low temperatures, and the maximum output is reduced.

  As a countermeasure for this, Patent Document 1 below proposes a method of varying the overcurrent protection value according to the temperature. Further, in Patent Document 2 below, a method for heating a magnet by transferring heat to a magnet by changing an energization frequency and using an iron loss accompanying a change in frequency in addition to a copper loss due to heat generation of a winding. Is disclosed.

Japanese Patent Application Laid-Open No. 07-067390 JP 2013-179726 A

  However, in the prior art disclosed in Patent Document 1, when the overcurrent protection value is changed by software, there is a problem that processing delay time occurs when the current increases instantaneously. There is a problem that the cost increases because it is necessary to have a plurality of circuits.

  On the other hand, in the prior art of Patent Document 2, in the case of a motor having a large inductance, there is a problem that high-frequency current hardly flows and iron loss does not occur sufficiently. In recent years, thin magnetic steel sheets tend to be used due to the need for higher efficiency, and it takes time for the magnet temperature to reach a desired temperature because both copper loss and iron loss are small. There was a problem.

  This invention is made | formed in view of the above, Comprising: It aims at obtaining the air conditioner which can suppress the demagnetization of a permanent magnet, suppressing the increase in cost.

In order to solve the above-described problems and achieve the object, an air conditioner according to the present invention is an air conditioner including a permanent magnet type motor using a ferrite magnet for a rotor, The stator includes a back yoke and a plurality of teeth provided on the inner side of the back yoke and extending from the back yoke toward the center of the stator, and each of the plurality of teeth is made of an aluminum wire in a high space winding. The aluminum wires wound around each of the teeth adjacent to each other in the rotation direction of the rotor are in contact with each other through an insulating material, and the aluminum wires are restrained and energized without driving the permanent magnet type motor. To heat the ferrite magnet.

  According to the present invention, it is possible to suppress the demagnetization of the permanent magnet while suppressing an increase in cost.

The block diagram of the air conditioner which concerns on embodiment of this invention AA arrow sectional view of the fan motor shown in FIG. Enlarged view of compressor BB arrow sectional drawing of the compressor motor shown in FIG. Diagram showing the relationship between ferrite magnet temperature, demagnetization limit current value, and overcurrent protection value

  Hereinafter, an air conditioner according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of an air conditioner 100 according to an embodiment of the present invention. The air conditioner 100 converts the AC voltage supplied from the commercial power supply 70 into a DC voltage, and the compression converts the DC voltage from the converter circuit 62 into an AC voltage that can be driven by the compressor motor 20B. Machine motor inverter circuit unit 60, a fan motor inverter circuit unit 61 that converts a DC voltage from the converter circuit unit 62 into an AC voltage that can be driven by the permanent magnet type fan motor 20A, and an indoor unit fan 41 or A permanent magnet type fan motor 20A that is a drive source of the fan 43 for the outdoor unit, an indoor heat exchanger 40 that performs heat exchange by circulating the refrigerant, and an outdoor heat exchange that performs heat exchange by circulating the refrigerant. It comprises a cooler 42, a four-way valve 50 for switching between cooling and heating flow paths, an expansion valve 52 for expanding the refrigerant, and a compressor 30 for compressing the refrigerant. In the figure, the solid line of the four-way valve 50 is the refrigerant flow during the heating operation, and the dotted line is the refrigerant flow during the cooling operation.

  The compressor 30, the four-way valve 50, the outdoor heat exchanger 42, the expansion valve 52, and the indoor heat exchanger 40 are connected by a refrigerant pipe 51 to constitute a refrigeration cycle 80. A compressor mechanism 31 that compresses the refrigerant and a compressor motor 20B that operates the compressor mechanism 31 are provided inside the sealed container 32 of the compressor 30. A mechanism such as scroll, rotary, or reciprocating is used for the compression mechanism 31.

  The operation of the air conditioner 100 will be described. The AC voltage supplied from the commercial power source 70 is converted into a DC voltage by the converter circuit unit 62, and is converted into an AC voltage having a frequency and voltage required by the compressor motor 20B in the compressor motor inverter circuit unit 60, and compressed. Is supplied to the machine motor 20B. The DC voltage converted by the converter circuit unit 62 is converted into an AC voltage having a frequency and voltage required by the fan motor 20A in the fan motor inverter circuit unit 61 and supplied to the fan motor 20A.

  2 is a cross-sectional view of the fan motor 20A shown in FIG. The illustrated fan motor 20A includes a stator 1, a rotor 2 disposed on the inner diameter side of the stator 1, two bearings 3 that rotatably support a shaft 4 penetrating through the center of the rotor 2, and a fan motor 20A. And the mold resin 9 constituting the housing 13 surrounding the outer ring of the bearing 3 disposed on one end side of the stator 1 and the mold resin 9 surrounding the outer ring of the bearing 3 disposed on the other end side of the stator 1. And a bracket 5 to be fitted into the inner peripheral surface of the opening formed in the above.

  The stator 1 includes a stator core 1a formed by caulking a plurality of electromagnetic steel plates punched into a specific shape, and laminating them while welding or bonding, a winding 1b wound around a tooth (not shown) of the stator core 1a, and an insulating material 1c. Composed. The rotor 2 includes a resin portion 2a provided on the outer peripheral portion of the shaft 4 and a ferrite magnet 2b disposed on the resin portion 2a.

  FIG. 3 is an enlarged view of the compressor 30. FIG. 3 shows some of the components of the compressor 30, and the same components as those of the fan motor 20A of FIG. The stator core 1a fixed by press fitting, shrink fitting or cold fitting to the inner peripheral surface of the sealed container 32 shown in FIG. 3, the winding 1b wound around the stator core 1a, and the rotor arranged on the inner diameter side of the stator core 1a 2, a shaft 4 that is rotatably held by bearings (not shown) provided at the upper and lower portions of the compressor 30 and penetrates the rotor 2, and the rotation of the rotor 2 causes the low-temperature and low-pressure refrigerant gas to be heated to a high temperature. A compressor 30 that discharges as high-pressure refrigerant gas is shown. The stator core 1a and the winding 1b shown in FIG. 3 are examples of components of the stator 1, and the stator 1 and the rotor 2 constitute a compressor motor 20B.

  4 is a cross-sectional view of the compressor motor 20B shown in FIG. As shown in FIG. 4, the stator 1 includes an insulating material 1c including an inter-winding insulating material 1c1 and a teeth coating insulating material 1c2 in addition to the stator core 1a and the winding 1b. The stator core 1a includes an annular back yoke 1a1 and a plurality of teeth 1a2 that are arranged at regular intervals in the rotational direction on the inner diameter side of the back yoke 1a1 and extend from the back yoke 1a1 toward the center of the stator core 1a. A plurality of slots 1a3, which are spaces defined by the back yoke 1a1 and the teeth 1a2, are formed. In the stator 1, a winding 1 b is wound around a tooth 1 a 2 insulated by a tooth covering insulating material 1 c 2. In the illustrated example, nine teeth 1a2 are formed on the stator core 1a, but the number of teeth 1a2 is not limited to this.

  The stator core 1a is configured by laminating thin electromagnetic steel sheets whose surfaces are coated with an insulating coating in order to prevent eddy currents due to changes in magnetic flux. The insulating material 1c is made of a film or resin. An example of the film is PET polyethylene terephthalate, PEN polyethylene naphthalate, PPS polyphenylene sulfide, or TLT (PET / PPS composite film). An example of the resin is PBT polybutylene terephthalate, PPS polyphenylene sulfide, LCP liquid crystal polymer, or BMC bulk molding compound.

  In the stator 1 shown in FIG. 4, among the plurality of windings 1b wound around each tooth 1a2, the adjacent windings 1b are insulated by the interwinding insulating material 1c1, and the winding 1b and the interwinding insulating material 1c1 are insulated. Are in close contact. If the reliability can be ensured, the inter-winding insulating material 1c1 may be omitted, and the insulating property may be given only by the insulating coating applied to the surface of the winding 1b.

  The rotor 2 is provided with a cylindrical resin portion 2a formed by caulking a plurality of electromagnetic steel sheets punched into a specific shape, and laminating them while welding or bonding, and is provided at regular intervals in the rotation direction corresponding to the number of magnetic poles. A plurality of magnet insertion holes 2c, a ferrite magnet 2b having a shape corresponding to the shape of each magnet insertion hole 2c and inserted into the magnet insertion hole 2c, and a shaft insertion hole 2d formed at the radial center of the resin portion 2a Have A sintered magnet or a bonded magnet is used for the ferrite magnet 2b.

  Here, the winding method of the winding 1b used for the fan motor 20A and the compressor motor 20B is roughly classified into concentrated winding and distributed winding, and concentrated winding is adopted as an example in the present embodiment.

  In general, a general-purpose copper wire having a low resistance is used for the winding. However, in the fan motor 20A and the compressor motor 20B according to the present embodiment, an aluminum winding having a resistivity 1.6 times that of copper is used. Line 1b is used.

  In addition, the stator 1 according to the present embodiment is highly space-wound with a winding 1b that is an aluminum wire. High space means that an aluminum wire touches an aluminum wire wound around adjacent teeth, or touches an insulating material for insulation between aluminum wires and between cores. Even in an aluminum wire whose conductivity is 0.57 times that of a copper wire, Joule heat due to energization can be effectively transmitted to the ferrite magnet 2b.

  In the following description, the fan motor 20A and the compressor motor 20B are simply referred to as “motors”, and unless otherwise specified, the compressor motor inverter circuit unit 60 and the fan motor inverter circuit are described unless otherwise specified. The unit 61 is simply referred to as an “inverter circuit”.

  FIG. 5 is a diagram showing the relationship among the temperature of the ferrite magnet 2b, the demagnetization limit current value, and the overcurrent protection value. The horizontal axis represents the temperature of the ferrite magnet 2b, and the vertical axis represents the demagnetization limit current value of the ferrite magnet 2b corresponding to the temperature of the ferrite magnet 2b.

  Since the ferrite magnet 2b has a property that the coercive force decreases as the temperature decreases, the proof strength against the reverse magnetic field generated by the stator current decreases as the temperature decreases, and the magnet becomes easily demagnetized. The demagnetization limit current value represents a stator current that may cause a demagnetization rate of several percent that affects the characteristics with respect to the initial magnetic force of the magnet. In consideration of the demagnetization characteristics of the ferrite magnet 2b, The temperature is low in the low temperature region, and increases as the temperature of the ferrite magnet 2b increases. When a stator current exceeding the demagnetization limit current value is supplied to the stator 1, the magnetic force of the rotor 2 is reduced. Therefore, an overcurrent protection value is set in the air conditioner 100 so that the stator current does not exceed the demagnetization limit current value. When the stator current exceeds the overcurrent protection value, the air conditioner 100 The motor is stopped by turning off the power, or stall control is performed immediately before the stator current exceeds the overcurrent protection value so that the stator current does not exceed the overcurrent protection value.

  T1 is a lower limit temperature within the use range of the air conditioner 100, T3 is a magnet temperature at the maximum output, and T2 is a magnet temperature higher than T1 and lower than T3. P1 is an overcurrent protection value that is set so that the stator current that flows when the magnet temperature is T1 does not exceed the demagnetization limit current value I1. P2 is an overcurrent protection value that is set so that the stator current that flows when the magnet temperature is T2 does not exceed the demagnetization limit current value I2. P3 is an overcurrent protection value that is set so that the stator current that flows when the magnet temperature is T3 does not exceed the demagnetization limit current value I3.

  Thus, the overcurrent protection value is normally set to the demagnetization limit current value I1 so that demagnetization does not occur even when the air conditioner 100 is started at the lower limit temperature T1 within the use range. However, the stator current actually approaches the demagnetization limit at the maximum output, and the magnet temperature at that time reaches T3. Although the demagnetization limit current value at this time is I3, since the demagnetization limit current value I1 is set in the air conditioner 100 in consideration of demagnetization at a low temperature, the demagnetization limit current value is used as the stator current. It can only flow up to I1.

  As a countermeasure against this, Patent Document 1 proposes a method of varying the overcurrent protection value according to temperature. However, when the overcurrent protection value is changed by software, processing delay time occurs when the current rises instantaneously, and when it is executed by hardware, the cost of having to have multiple circuits is increased. Invite. Therefore, the method of changing the overcurrent protection value depending on the temperature is generally not adopted in the air conditioner 100.

  As another countermeasure, a method of starting after heating the magnet until the magnet temperature reaches a desired temperature is conceivable. In the present embodiment, in order to simplify the description, T2 shown in FIG. 5 is defined as “desired temperature”.

  As a conventional method for increasing the magnet temperature, there is a method in which the motor is heated by a heater without starting the motor at a low temperature, and the motor is started after the heating. However, this method has a problem of cost because the heater is mounted. As another heating method, there is a heaterless method by energizing the windings to generate heat in the stator. However, in this method, only a current less than the demagnetization limit current value can be applied, and there is a problem that it takes time until the magnet temperature reaches a desired temperature.

As another method for raising the magnet temperature, the energization of the windings represented by I ² R is performed by driving the switching elements constituting the inverter circuit and energizing the windings without rotating the rotor 2. There is one that generates a loss and transfers this heat to the magnet to heat the magnet. I represents current and R represents winding resistance. Joule heat loss is also called copper loss because copper wire is generally used.

  As a method of restraint energization, there are a method of energizing direct current, a method of energizing a high-frequency alternating current that does not follow the rotation of the rotor 2, or a method of energizing two phases by dephasing one phase. In any method, a current can be generated by the switching elements constituting the inverter circuit, and the carrier frequency of the current is generated by switching at 16 kHz or higher which is not problematic as noise during energization heating. In addition, when an alternating current is applied, not only the copper loss but also the iron loss generated in the core due to the change in magnetic flux accompanying the change in current can be used as heat. However, in these constrained energization methods, copper loss can be generated only with a current less than the demagnetization limit current. Therefore, it takes time until the magnet temperature reaches a desired temperature.

  In particular, in the case of concentrated winding that is often employed in small motors and high-efficiency motors, the amount of heat generated is small because the winding circumference is short and the winding resistance is small. In addition, a stator core of a type divided for each tooth and a stator core of a thin type that can be wound with a wide core can be wound so that winding can be performed at high density. Rather, a thick winding can be used. Therefore, when concentrated winding is adopted for these types of stator cores, the copper loss becomes smaller, and it takes more time until the magnet temperature reaches a desired temperature.

  On the other hand, with respect to iron loss, in recent years, since the motor efficiency has been improved by reducing the iron loss of the electrical steel sheet constituting the core, the amount of heat generation is also decreasing. In order to reduce iron loss, electrical steel sheets have been made thinner than the 0.5mm thickness, which has been the mainstream in the past, and the thickness of the electrical steel sheets has been reduced to 0.35mm, 0.3mm, and 0.25mm. Then, eddy current loss accompanying high frequency is particularly reduced among iron losses. Therefore, iron loss heat generation due to high-frequency energization becomes small, which is one of the factors that takes time until the magnet temperature reaches a desired temperature. In particular, concentrated winding motors have a large ratio of iron loss to copper loss, and as a result, thin electromagnetic steel sheets, for example, those with a thickness of 0.35 mm or less are often used, and both copper loss and iron loss are small. It takes time for the magnet temperature to reach the desired temperature.

Therefore, the fan motor 20A and the compressor motor 20B according to the present embodiment are preheated by winding the aluminum winding 1b in the slot 1a3 of the stator 1 in a high space and energizing the winding 1b with restraint. Is configured to do. Since the resistivity of the aluminum wire is 1.6 times that of the copper wire, the Joule heat loss of the aluminum wire represented by I ² R is the Joule heat generated in the copper wire when the current value is the same. 1.6 times the loss. Therefore, even when the current is less than the demagnetization limit current value, the time until the magnet temperature reaches the desired temperature can be shortened. An example of restraint energization to the compressor motor 20B is realized by a switching operation of the switching element constituting the compressor motor inverter circuit unit 60, and an example of restraint energization to the fan motor 20A is for a fan motor. This is realized by the switching operation of the switching elements constituting the inverter circuit unit 61.

  However, since the thermal conductivity of the aluminum wire is as small as 0.57 times that of the copper wire, it is disadvantageous in terms of transferring heat generated by the aluminum wire to the magnet. In order to efficiently transfer the heat generated in the aluminum wire to the magnet, the aluminum wire is brought into close contact with each other to reduce the gap between the aluminum wires, or the aluminum wire is brought into close contact with the tooth to make the aluminum wire and the tooth It is desirable to reduce the gap between the two. In addition, although the aluminum wire wound around the teeth inevitably adheres to the teeth, a gap is generated between adjacent aluminum wires.

  Therefore, in this embodiment, air insulation, which is often employed in a motor using a copper wire, is not performed, and the adjacent windings 1b are insulated by an interwinding insulating material 1c1, thereby at least one turn. The winding 1b is closely attached to the inter-winding insulating material 1c1. As an example of the inter-winding insulating material 1c1, the above-described film or resin insulating material formed into pieces may be inserted between adjacent windings 1b, or between adjacent windings 1b. You may make it integrally mold with resin. If the reliability is determined to be sufficient by the insulating coating applied to the surface of the winding 1b, the adjacent windings 1b may be brought into close contact with each other.

  In the air conditioner 100 according to the present embodiment, preheating is performed as follows. Based on the temperature measured by a temperature sensor (not shown) installed in the air conditioner 100, the winding resistance, the restrained energizing current value, the energizing current frequency, and the energizing time, a database is created in advance through experiments. Preheating is performed until the magnet temperature estimated from the above reaches a desired temperature. That is, preheating is performed until the magnet temperature reaches the temperature at which it is determined that the stator current has exceeded the overcurrent protection value P2. Thereafter, the air conditioner 100 performs normal activation.

  Note that changing the winding 1b from a copper wire to an aluminum wire also increases the Joule heat loss of the winding 1b during normal operation and reduces the motor efficiency, but the reduction in motor efficiency increases the magnet size. Can be offset. The motor torque T is simply expressed as T∝n · I · φ, and if the magnet size is increased to increase the magnetic flux φ, the motor torque T can be generated even if the current I is small. By reducing the current, it is possible to suppress Joule heat loss during normal operation, which is increased due to the aluminum wire. Also, by increasing the magnet size, it is possible to increase the resistance against demagnetization, increase the demagnetization limit current value, and increase the overcurrent protection value. By increasing the overcurrent protection value, it is possible to increase the energization current at the time of restraint energization, and the time until the magnet temperature reaches a desired temperature can be further reduced.

  Further, when the low-temperature demagnetization of the ferrite magnet 2b is alleviated by energization heating, a magnet having a high magnetic force becomes easy to use. An example of a high magnetic force magnet is a rare earth magnet. In magnets, there is a trade-off relationship between the coercive force, which is an index of demagnetization resistance, and the residual magnetic flux density, which is an index of the amount of magnetic flux.If a magnet with a lower coercive force can be used, higher magnetism can be achieved, Torque can be generated with less current, improving efficiency. Regarding the increase in cost due to the increase in magnet size, the cost can be significantly reduced by changing the winding 1b from an expensive copper wire to an inexpensive aluminum wire. Therefore, the magnet size is comprehensively determined to be an appropriate value including the target value of the motor efficiency.

  In addition, since the linear expansion coefficient of the aluminum wire is 1.35 times the linear expansion coefficient of the copper wire, when the winding is changed from the copper wire to the aluminum wire, in particular, the winding 1b and the lead wire that goes out of the motor Attention should be paid to the quality at the connection part. Copper wire is often used for the lead wire that goes out of the motor due to strength problems, and the connection between the aluminum winding 1b and the copper lead wire is when the copper metal terminal is mechanically caulked. There is. There are other connection methods such as fusing, ultrasonic vibration welding, soldering, or brazing. However, in any connection method, a current heat shock due to restrained energization causes a force to peel the connection part due to the difference in the coefficient of linear expansion between copper and aluminum. Even if such a force is applied, the necessary contact resistance at the connection part can be satisfied if the necessary minimum adhesion force is generated, but if a gap occurs in the connection part and oxygen enters the part, it is easily oxidized. An oxide layer, which is an insulating layer, is generated on the surface of aluminum, which may result in poor contact. Therefore, it is necessary to isolate the connection portion from oxygen so that this oxidation does not occur. As an isolation method, it is necessary to mold the connection part, or to arrange the connection part in a sealed space that is blocked from outside air, such as the compressor 30.

  Although the countermeasure for low-temperature demagnetization of the magnet, which is one of the purposes of the electric heating, has been described, the following will describe the prevention of refrigerant stagnation of the compressor 30 which is another purpose of the electric heating. In general, in a heat pump refrigeration apparatus in which the indoor heat exchanger 40 and the outdoor heat exchanger 42 are connected to the compressor 30 via the refrigerant pipe 51, the cooling of the heat pump refrigeration apparatus is performed when the compressor 30 is shut down. There is a tendency that the refrigerant moves and condenses in the part where it is formed.

  As an example, when the heating operation is stopped at night, the temperature of the indoor heat exchanger 40 is higher than the temperatures of the compressor 30 and the outdoor heat exchanger 42, so the compressor 30 and the outdoor heat exchanger 42 are connected to the indoor side. The refrigerant in the heat exchanger 40 moves. In addition, since the heat capacity of the compressor 30 is larger than that of the outdoor heat exchanger 42, when the outside air temperature rises in the morning, the temperature of the outdoor heat exchanger 42 rises earlier than the temperature of the compressor 30. The refrigerant in the outer heat exchanger 42 moves to the compressor 30 side where the temperature is lower than that of the outdoor heat exchanger 42 and condenses, into the oil in the oil sump space provided in the sealed container 32 of the compressor 30. A refrigerant stagnation phenomenon occurs in which the liquid refrigerant melts and accumulates. Due to the stagnation of the refrigerant, the liquid refrigerant dilutes the oil in the oil sump space, and when the compressor 30 is restarted, the liquid refrigerant dissolved in the oil in the oil sump space is formed into bubbles and eluted. A phenomenon may occur, or liquid compression may occur due to the compressor 30 directly sucking the liquid refrigerant, causing the compressor 30 to malfunction.

  In the air conditioner 100 according to the present embodiment, the refrigerant in the compressor 30 is heated until the desired temperature is reached by energizing the compressor motor 20B before the compressor 30 is started, and the liquid refrigerant. Vaporize to prevent sleep activation. In the case of the compressor 30, the desired temperature is appropriately determined based on the temperature for relaxing the demagnetization of the ferrite magnet 2b and the temperature for preventing stagnation.

  In the air conditioner 100 according to the present embodiment, both the fan motor 20A and the compressor motor 20B are used. However, only one of the fan motor 20A and the compressor motor 20B may be used for the air conditioner 100. Good.

  The rotor 2 according to the present embodiment is an IPM (Interior Permanent Magnet) type in which the ferrite magnet 2b is inserted into the magnet insertion hole 2c. However, the present invention is not limited to this, and a magnet is disposed on the outer peripheral surface of the resin portion 2a. An SPM (Surface Permanent Magnet) type may be used.

  Further, the stator core 1a and the resin portion 2a according to the present embodiment are not limited to those obtained by laminating electromagnetic steel plates, but are integrated cores obtained by processing steel materials, resin cores obtained by mixing resin and iron powder, or magnetism A powder core obtained by pressure-molding powder may be used, and the type of the core is selected depending on the purpose and application.

Embodiment 2. FIG.
The air conditioner 100 according to Embodiment 2 uses both the fan motor 20A and the compressor motor 20B, and is configured to energize the fan motor 20A while energizing the compressor motor 20B.

  Depending on the internal structure of the air conditioner 100, the compressor 30 may stay as a liquid refrigerant in the compressor 30 regardless of the motor design. In order to prevent stress of the compression mechanism 31 due to oil dilution or liquid compression due to the retention of the liquid refrigerant, there is a case where restraint energization is unavoidable. On the other hand, since the fan motor 20A is not used in the refrigeration circuit, the fan motor 20A is not affected by the liquid refrigerant and is concerned only about the low temperature demagnetization of the ferrite magnet 2b. As a countermeasure for this, there is a means other than energization such as increasing the coercive force of the magnet. However, increasing the coercive force of the magnet results in a decrease in the amount of magnetic flux and an increase in cost. Therefore, a system as an air conditioner should be built while suppressing performance degradation and cost increase.

  Therefore, in the air conditioner 100 according to Embodiment 2, the fan motor 20A is also energized in a restricted manner using the time during which the energization of the compressor motor 20B is energized. As a result, measures to increase the coercive force of the ferrite magnet 2b used in the fan motor 20A, that is, measures against low-temperature demagnetization without using an expensive magnet typified by a rare earth magnet can be realized, thereby realizing a low-cost fan motor 20A. it can. In general, the fan motor 20A has a smaller heat capacity than the compressor motor 20B, so that it is sufficient to perform energization for a shorter time than the compressor motor 20B, and the compressor motor 20B and the fan motor 20A are energized simultaneously. By performing, it can shorten time until the magnet temperature reaches desired temperature as the air conditioner 100 whole as compared with the case where restraint energization is separately performed.

Embodiment 3 FIG.
The air conditioner 100 according to the third embodiment has a configuration in which the energization method is mainly AC energization in the compressor motor 20B and mainly DC energization in the fan motor 20A.

  The fan motor 20A has a motor load torque that is less than half that of the compressor motor 20B, a rotational speed of use that is about 1/3 that of the compressor motor 20B, a small output, and a small current value. On the other hand, since the fan motor 20A has a smaller amount of magnets than the compressor motor 20B, the magnetic force is small, and since the maximum rotation speed is smaller than that of the compressor motor 20B, the induced voltage per turn of the winding is small.

  Here, the circuit equation of the permanent magnet type motor is simply expressed as VE = IZ. V is the maximum inverter output voltage determined by the bus voltage of the converter circuit 62, E is the induced voltage determined by E = n · dφ / dt, I is the winding current, Z is the motor impedance, n is the number of turns of the winding, φ is The magnetic flux amount, d / dt, represents time differentiation. The motor torque is simply expressed as T∝n · I · φ, and the induced voltage E is controlled to be less than the maximum inverter output voltage in order to obtain a torque by passing a current. However, the fan motor 20A is a compressor motor. Compared to 20B, since the maximum rotation speed and the amount of magnetic flux are small, dΦ / dt is small and the number of turns n can be increased accordingly. If the number of turns n is increased, torque can be generated with a current smaller than T∝n · I · φ, and if the current is small, the inverter circuit element can be reduced in capacity, and the efficiency of the inverter circuit can be increased. Can be improved.

  However, as the number of turns n increases, the inductance increases and the amplitude of the high-frequency alternating current decreases. Considering this together with the method of restraint energization, in the case of DC energization, Joule heat loss due to the winding is mainly, and iron loss heat generation due to high frequency components superimposed on DC is small. Since AC energization causes iron loss in the core due to changes in magnetic flux generated by AC, heat generation due to iron loss mainly occurs in restraint energization due to AC energization.

  In the fan motor 20A, since the number of turns n is large and the inductance L is large, particularly when the carrier frequency f of the inverter circuit is high, the impedance (= 2πfL) determined by the inductance and the frequency becomes large, the AC current amplitude cannot be increased, and the iron loss heat is generated. Will be small. The carrier frequency f is a value of 16 kHz or more that is less likely to cause a problem as noise during energization heating.

  Therefore, it is desirable that the energization method for the fan motor 20A is mainly DC energization that can increase the winding Joule heat loss more than the iron loss. The main component of DC energization is that an AC component may be superimposed on the current at the time of restraint energization, but a current greater than the ratio of the AC component to the current at the time of restraint energization is energized. Or the DC energization time at the time of restraint energization is longer than the AC energization time.

  On the other hand, since the compressor motor 20B has a small inductance, the current amplitude can be made larger than that of the fan motor 20A. Therefore, as a method of restraint energization for the compressor motor 20B, heat is generated by both iron loss and winding Joule heat loss. It is desirable to mainly use AC power that is possible. The main component is AC energization, but a DC component may be superimposed on the current at the time of restraint energization, but a current having a ratio of the AC component to the current at the time of restraint energization greater than the ratio of the DC component to the current at the time of restraint energization This indicates that the AC energization time at the time of restraint energization is longer than the DC energization time.

  The fan motor 20A is described as having a larger inductance than the compressor motor 20B. The reason is that the maximum output voltage of the fan motor inverter circuit unit 61 is higher than the maximum output voltage of the compressor motor inverter circuit unit 60. In the case of a general air conditioner, the bus voltage of the common converter circuit unit 62 is branched into the fan motor inverter circuit unit 61 and the compressor motor inverter circuit unit 60, and the required maximum rotational speed is the fan motor 20A. This is because it is lower.

Embodiment 4 FIG.
In the air conditioner 100 according to the fourth embodiment, the switching element that constitutes the inverter circuit that drives the motor is composed of a wide band gap semiconductor. The switching element of the inverter circuit that generates the applied voltage and current at the time of energization is generally a Si-based semiconductor made of Si silicon, but materials such as SiC silicon carbide, GaN gallium nitride, and C diamond are used. Since the used wide band gap semiconductor has a small switching power loss, it is possible to suppress the power loss at the time of restraint energization by configuring the switching elements constituting the inverter circuit with the wide band gap semiconductor.

  As described above, in the air conditioner 100 according to the present embodiment, the fan motor 20A, which is a permanent magnet type motor, and the stator 1 of the compressor motor 20B are wound in high space with aluminum wires, and the fan motor 20A and The ferrite magnet 2b is heated by energizing the aluminum wire without driving the compressor motor 20B. By winding the aluminum winding 1b on the stator 1 in a high space, heat generation increases even at a current less than the demagnetization limit current, and the time until the magnet temperature reaches a desired temperature can be shortened. Even when an aluminum wire having a degree lower than that of a copper wire is used, Joule heat generated by energization can be effectively transmitted to the ferrite magnet 2b. Therefore, in the air conditioner 100 according to the first to fourth embodiments, the current protection value can be changed by software without causing a processing delay time and the current protection value can be changed by hardware. The demagnetization of the permanent magnet can be suppressed without increasing the cost.

  Moreover, in the air conditioner 100 according to the present embodiment, the aluminum wire is wound around the stator 1 by concentrated winding. Concentrated windings have a shorter winding circumference than distributed windings, so Joule heat, which is the heat generated by the windings, is small. On the other hand, since the magnetic flux becomes unbalanced with respect to the distributed winding, the iron loss becomes large. By combining with the aluminum winding 1b, the time until the magnet temperature reaches a desired temperature can be shortened by using Joule heat loss and iron loss due to the resistance of the winding 1b.

  Further, the stator 1 of the air conditioner 100 according to the present embodiment includes a compressor motor 20B that drives the compressor 30 mounted on the air conditioner 100, and a fan 41 and a fan 43 mounted on the air conditioner 100. It is used for the fan motor 20A to be driven, and the fan motor 20A is also energized while the compressor motor 20B is energized. As a result, it is possible to shorten the time until the magnet temperature reaches a desired temperature in the air conditioner 100 as a whole, compared to when the compressor motor 20B and the fan motor 20A are separately energized.

  In the air conditioner 100 according to the present embodiment, the constraint energization is mainly AC energization in the compressor motor 20B, and mainly DC energization in the fan motor 20A. The compressor motor 20B capable of generating heat with both iron loss and winding Joule heat loss mainly uses AC energization, and the fan motor 20A where Joule heat loss due to the winding 1b dominates rather than iron loss mainly uses DC energization. By doing so, the time can be further shortened until the magnet temperature reaches a desired temperature.

  In addition, the air conditioner 100 according to the present embodiment includes a compressor motor inverter circuit unit 60 that drives the compressor motor 20B, and the switching element that constitutes the compressor motor inverter circuit unit 60 has a wide band gap. It is composed of a semiconductor. In addition, the air conditioner 100 according to the present embodiment includes a fan motor inverter circuit unit 61 that drives the fan motor 20A, and the switching elements that constitute the fan motor inverter circuit unit 61 are formed of a wide band gap semiconductor. Has been. Thereby, the power loss at the time of restraint energization can be suppressed.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

  1 Stator, 1a Stator Core, 1a1 Back Yoke, 1a2 Teeth, 1a3 Slot, 1b Winding, 1c Insulating Material, 1c1 Interwinding Insulating Material, 1c2 Teeth Covering Insulating Material, 2 Rotor, 2a Resin Part, 2b Ferrite Magnet, 2c Magnet insertion hole, 2d shaft insertion hole, 3 bearing, 4 shaft, 5 bracket, 9 mold resin, 13 housing, 20A fan motor, 20B compressor motor, 30 compressor, 31 compression mechanism, 32 sealed container, 40 indoor side Heat exchanger, 41 fan, 42 outdoor heat exchanger, 43 fan, 50 four-way valve, 51 refrigerant piping, 52 expansion valve, 60 compressor motor inverter circuit part, 61 fan motor inverter circuit part, 62 converter circuit part 70 Commercial power, 80 Refrigeration cycle, 100 Air Sum machine.

Claims (7)

An air conditioner equipped with a permanent magnet type motor using a ferrite magnet as a rotor,
The stator of the permanent magnet motor is
Back yoke,
A plurality of teeth provided inside the back yoke and extending from the back yoke toward the center of the stator;
With
Each of the plurality of teeth is wound in high space with an aluminum wire,
The aluminum wires wound around each of the teeth adjacent in the rotation direction of the rotor are in contact with each other via an insulating material,
An air conditioner that heats a ferrite magnet by energizing the aluminum wire without driving the permanent magnet motor.   The air conditioner according to claim 1, wherein the aluminum wire is wound around the stator by concentrated winding. The stator is used for a compressor motor that drives a compressor mounted on the air conditioner and a fan motor that drives a fan mounted on the air conditioner,
The air conditioner according to claim 1 or 2, wherein the fan motor is also energized with restraint while the compressor motor is energized with restraint. By making the number of turns of the aluminum wire of the stator used for the fan motor larger than the number of turns of the aluminum wire of the stator used for the compressor motor, the inductance of the fan motor is made more than the inductance of the compressor motor. And make it bigger
The air conditioner according to claim 3, wherein the restraint energization is mainly AC energization in the compressor motor, and mainly DC energization in the fan motor. Having an inverter circuit for a compressor motor for driving the compressor motor;
The air conditioner according to claim 3 or 4, wherein the switching element constituting the compressor motor inverter circuit section is formed of a wide band gap semiconductor. A fan motor inverter circuit unit for driving the fan motor;
The air conditioner according to claim 3 or 4, wherein the switching element constituting the fan motor inverter circuit section is formed of a wide band gap semiconductor.   The air conditioner according to any one of claims 1 to 6, wherein the insulating material is an interwinding insulating material.

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